Goldenwrench BLACKLINE Billet Coolant Expansion Tank Cap Cover for BMW M Vehicles – N55, S55, S63, S65
Upgrade the look of your BMW M engine bay with the Goldenwrench BLACKLINE billet coolant expansion tank cap cover. Engineered for popular BMW M engines – N55, S55, S63 and S65 – this premium CNC machined T6 aluminium cap cover delivers a factory-plus finish with a durable anthracite grey anodised colour that complements the OEM engine cover. If you are searching for a BMW coolant cap cover, BMW M coolant cap cover, billet coolant cap, aluminium coolant expansion tank cap cover or engine bay dress-up for BMW M2, M3, M4 or M5, this is the must-have aesthetic upgrade.
Designed and produced by Goldenwrench, the BLACKLINE Performance cap cover features precision 3D-milled logos and detailing for a crisp, premium appearance. It is not a full cap replacement – the billet cover securely affixes to the top of the factory coolant cap and installs in minutes using the included instructions. The result is a clean, high-end look that elevates your engine bay without affecting OEM functionality.
Why enthusiasts choose this BMW coolant expansion tank cap cover
- Premium materials – CNC formed from T6 aluminium with anthracite grey anodised colour
- Precision finish – 3D-milled logos and decorations for a true billet look
- OEM-friendly – cap cover fits over the factory coolant cap (not a full replacement)
- Quick install – simple, tool-free fitment in minutes with supplied instructions
- Perfect match – designed to complement the BMW M engine cover for a cohesive finish
- Engine bay dress-up – subtle but impactful visual upgrade for any BMW M build
At Nforcd, we run this cap cover on our own cars and our customers love the premium feel and quality. If you are browsing for BMW M coolant cap cover, BMW radiator expansion tank cap cover, BMW reservoir cap cover, BMW M2 M3 M4 M5 coolant cap, or Goldenwrench BLACKLINE coolant cap cover, you are in the right place.
Compatibility – BMW models and engines
This BLACKLINE billet coolant expansion tank cap cover fits most BMW vehicles equipped with the large coolant tank and the following engines: N55, S55, S63 and S65. Always check your factory coolant cap shape matches the product photos.
- BMW M235i (2014–2020, F22)
- BMW M2 and M2 Competition (2015–2021, F87)
- BMW M3 (2007–2019, E90 E91 E92 F80)
- BMW M4 (2014–2020, F82)
- BMW M5 and M5 Competition (2011+, F10 F90 G90)
Common search terms for this item include: BMW coolant expansion tank cap cover, BMW M coolant cap cover, BMW billet coolant cap, BMW aluminium coolant cap cover, BMW engine bay dress up, Goldenwrench coolant cap, BLACKLINE Performance coolant cap cover, BMW N55 coolant cap, BMW S55 coolant cap, BMW S63 coolant cap, BMW S65 coolant cap, BMW M2 coolant cap cover, BMW M3 coolant cap cover, BMW M4 coolant cap cover, BMW M5 coolant cap cover, F80 M3 coolant cap, F82 M4 coolant cap, F87 M2 coolant cap, F22 M235i coolant cap, F10 F90 G90 M5 coolant cap.
What is included
- 1 x Goldenwrench Supply BLACKLINE Coolant Expansion Tank Cap Cover
- Installation instruction card
Fitting and advice
Installation is straightforward – the billet cover affixes to the top of your factory coolant cap and can be installed in minutes. For professional fitting, we can help. Nforcd is based in Warwickshire and offers installation services – request a quote at Sales@nforcd.com.
Note: This is a cap cover that fits over the OEM coolant cap. It is not a full cap replacement. Please confirm your coolant cap shape matches the product images before ordering.